35mastr

My Th 400 trans came out of a 68 olds 88. It has no provisions for a speedometer.Its still casted shut. Is there any kind of tailshaft that can be installed that has a provision for the speedometer. Then I could just install the gear on the shaft. I have been searching the net for hours to just come up short on this issue.

tru-blue 442

George, I belive the 68-69 88's had
the speedo cable attached to the driver
side front wheel somehow.
I am not sure how to go about fixing
this problem. I think that where it
should fit is a plug that can be popped out
but I am not sure. You would then have to
drill and tap the spot for the retainer bolt.

35mastr

I know it was driven from the front wheel. It is still casted over and no plug can be removed. Thats why I was trying to figure out a tailshaft solution. I am sure that someone here has done this to get the speedo to work.

BILL DEMMER

my th400 s.p. came out of a '67 delta 88, it had a cup plug that was removed, then a drive gear was installed on the output shaft and the driven gear was installed into the tranny case.


bill

joe_padavano

Sorry, but you're SOL. Some of these TH400s came with a cup plug that could be knocked out, some with the hole cast shut. Short of disassembling the trans and having the hole machined in the case, there's nothing you can do. Swapping tailhousings doesn't help because the speedo provision is in the main case, not the tailhousing. Either get a GPS speedo or use the tach as a speedo.

35mastr

DO you have all the part numbers and tooth counts for the gears. Was the main shaft gear installed plastic or metal?

35mastr

From looking at the case,The main boss for the speedo is already machined into the case. Looks like the center needs to be taken out. I may just do it myself if it comes to that.

BILL DEMMER

i had my tranny guy do it along with a re-seal. i selected the combo based on my tires/rims/gear ratio.


bill